Tuesday

Exploring the very first galaxies is one of the major contemporary problems in astrophysics. We do not know when the first galaxies formed, nor how their formation occurred. This problem can be addressed best through deep imaging observations, particularly with the Hubble Space Telescope (HST) Frontier Fields (HFFs) program. In this study, we detect and examine the objects behind HFFs lensing cluster MACS0416-2403, Abell 2744 and their parallel fields. We have developed a novel method to subtract the massive galaxies from these clusters, allowing for a deeper and cleaner detection of the faintest systems. We present a photometric study of distant greater than 5 redshift galaxies using all 10 bands (HST, Spitzer and K-band). From this, we have created the first mass function for Frontier Fields. We further discuss how these results reveal new information on the faint-end of the mass function from the faintest galaxies at high-z.